"Part of it is obviously turning out real voters. But it's still, obviously, a small percentage of the entire electorate," he said.

Displaced residents can vote Monday through Thursday and Saturday at early voting stations in Lake Charles, Shreveport, New Orleans and seven other cities around the state. The offices will be closed for the Good Friday holiday.

Whelan said the buses are kicking off the early voting period "to send a message to other displaced residents, survivors, that it's important to participate - we need to participate to have a voice in whether and how the city is coming back."

The early voting stations are part of an emergency election plan for New Orleans. Traditional election-day voting in the city will be held on April 22 and absentee ballots also will be accepted.

The city had nearly a half-million people, about 70 percent of them black, before Hurricane Katrina. Those who have returned number fewer than 200,000, and most are white.

The election could help determine the city's rebuilding plan.

"Although typically 80,000 New Orleanians vote in the mayoral election, ACORN is very concerned that the lack of contact with the displaced electorate, both about news concerning the election as well as voting information," said Beaulah Labostrie, president of Louisiana ACORN.

Twenty-two candidates, most of them white, are challenging the re-election bid by Mayor Ray Nagin, who has been criticized in some quarters for his response to the hurricane. Challengers include Louisiana Lt. Gov. Mitch Landrieu and Audubon Institute chief executive Ron Forman.

If no mayoral candidate gets a majority of the votes in the nonpartisan primary, the top two finishers will compete in a May 20 runoff election.

Besides mayor, New Orleans voters will also be deciding seven City Council seats, seven assessors, a criminal sheriff, a civil sheriff, a civil court clerk, a criminal court clerk and a coroner.

Seven mayoral candidates fielded questions from displaced voters during a forum Saturday that was broadcast to evacuees in Texas communities of Houston, Dallas, San Antonio and Austin, as well as Shreveport and Baton Rouge.

"Do you want experienced leadership that is tried and tested? Or do you want to experiment at this important time in our city's history?" Nagin asked.

Evacuees pushed the candidates for answers to questions about restoring basic services, such as electricity and trash pickup.

"I cannot lie to you and tell you every single service in every single neighborhood is going to come back immediately," said Forman, an executive credited with turning New Orleans' zoo into a national showcase.